Brake testing structure



1386- 1934- R. J. NORTON BRAKE TESTING STRUCTURE 2 Sheets-Sheet l snowtot firm/v01 Mwmv Original Filed March 25, 1929 Dec. 25, 1934. J NORTON1,985,515

BRAKE TESTING S TRUCTURE Original Filed March 25, 1929 2 Sheets-Sheet 2Patented Dec. 1934 BRAKE TESTING STRUCTURE Raymond J. Norton,Washington, D. 0., assignor to Bendix-Cowdrey Brake Tester, Inc., NewYork, N. Y., 'a corporation- ,of Delaware Original application March 25,1929, Serial No.

Divided and this application January 25, 930, Serial No. 423,465 s orm.(01. 73-51) This application is a division of my copending applicationSerial No. 349,793 filed March 25, 1929 which has resulted in Patent No.1,946,101, dated Feb. 6,,1934. j

This invention relates to brake testing devices and pertains morespecifically to testing apparatus for automotive vehicles. I

In the-past a number of mechanisms for test,- ing the brakes onautomotive vehicles have been proposed. Many 01' these are adapted totest only one wheel at a time and hence necessitate a considerableexpenditure of time to complete the testing operation. Others areconstructed to test two or more wheels simultaneously, but are sodesigned as to preclude a facile adjustment to variant wheel baselengths and ready accessibility to the several brakes.

It .is an object of the present invention to provide a testing apparatuswhich simultaneously indicates the retardation of each of the wheelbrakes. Another object is to provide a testing apparatus for a vehiclehaving brakes on four wheels, .which is readily adjustable toaccommodate differential Yet another object is to provide a' testing'ap-' paratus of the class-described, which is-so designed as toprovidea clear space between the wheels on each side of the vehicle. e

A furtherobject is to provide anapparatus .which is adjustable tovarying wheel bases; and which is operable from a single source orpower.

With and. other important and related objects in view the inventioncontemplates the provision or a testing assembly which includes testingunits for the front and rear wheels in conjunction with a source ofpower which is adapted not only to actuate a plurality of the.

units, but also to relatively displace the units so as to accommodatecars of differential wheel bases.

in order to render the invention readily understood, a preferredmodification is shown in the accompanying drawings in which:

Figure 1 is a longitudinal vertical section of the present embodiment ofmy invention.

Figure 2 is .vertical section taken along the line 2-2 of Figure 1. 1

Figure 3 is a vertical section of one of my movable tester imits takenalong the line 3-3 of Figure L g Figure 4 is a horizontal section of thesame structure taken along the line 4-4 of Figurel.

Figure 5 is a vertical section along the line 5-5 of Figure 1',illustrating the manner of supporting and locking the movable trackways3.

, As shown in the. drawings, the apparatus com- 7 prises a pair ofparallel trackways 1, which are adapted to be set in a pit or mountedupon suitable supports and provided with a suitable ramp. The trackwaysmay be channel shaped in cross section and serve to receive the wheelsof the vehicle to be tested.

Positioned near one end of the trackway 1 is a second set of permanenttrackways 2. It will be noted that the trackways 2 are aligned with andspaced from the trackways' 1., Fitting in and bridging the space betweenthe tracks 1 and 2 are I the ways 2', which are secured to and movablewith the carriage 4. If desired, the lower edges of each A of the ways 3may be provided with anti-friction devices. 72 to diminish the slidingfriction between t them and'the permanent ways. All of the permanenttrackways are supported by a frame structure 73, which, together withthe tracks 6, is fixed to the base 74. 1 1

The carriage 4 is provided at its base with a plurality of rollers orwheels 5, which are mounted on the tracks or guideways 6. It will beseen that if a force is properly applied to the carriage, this may bedisplaced longitudinally and will carry with it the ways or runners 3.These latter will slide upon the permanent ways 1 and 2and will thusmaintain in efiect a continuous trackway for the reception and passageof a' vehicle wheel on and off the carriage. -Mounted on each carriageis a brake testing device designated generally by the numeral 7. As willbe described more in detail hereinafter, this is driven by a motorthrough a flexible driving connection and is adapted to rotate a wheelagainst-the resistance of its brake. The reaction or resistance set upby the brake is utilized to vary the tension on the driving mechanismand this variance is utilized to actuate a brake indicating device.

1 is a second testing device 8, comparable in most respects tothatmounted on the movable carriage 4. As has been indicatedhereinbefore, one object of the present invention is to providea testingunit for four wheel brakes which is adjustable longibases. In thepresentdevice, as will have beenappreciated; this adjustmentmay be madeby moving the carriage 4 longitudinally of the frame. The carriage '4 isdesigned to receive the .rear wheels of the vehicle, but it is obviousthat, if desired, the testing units for the rear wheels may .tudinallyto conform to cars of difierentwheel front wheels made displaceable, asby mounting them on movable carriages. Since the adjustment may readilybemade by moving only one set of testers at one end of the car, I preferto permanently fix the tester units 8 with respect to the frame. As-theunits 8. are relatively immovable, the trackway 1 may be closelyjuxtaposed thereto so that the front wheels of the vehicle may pass overthese ways and directly onto the testing units.

It is desirablefor obvious reasons to anchor the car to the testingdevice during the testing'operation. This mayreadily be done by securingthe car in any desired manner to the frame cross member 9. Where it isplanned to move the car forwardly on the trackways 1 and back it offafter the test is completed, this cross member may comprise a permanentmember which projects upwardly of the track. If, however, it is desiredto remove the car from the testing apparatus by moving it forwardly, thecross member 9 may be pivotally connected to the frame so that it may beswung downwardly and out of the path of the vehicle.

The movable carriages are usually positioned near the forward end of theassemblage, that is, in that position which will the shortest wheelbase. When a car is to be tested, it is moved onto the traokway untilthe front wheels rest on the driving rollers of the forward testingmachines. If the car has a wheel base which is longer the front and rearset of testers, the latter may be moved rearwardly until its rollers arein operative position beneath the rear driving wheels. The carriage maybe locked in this position by the pins 10, which are received inthe'aligned apertures 11 and 12 of the trackways 3 and 2, respectively.

To effect this displacement of the carriage a number of specificmechanisms maybe employed. If desired, the rear or driving wheels of theve-' hicle may be rotated by operation of the vehicle motor. Thesewheels frictionally engage the trackway 3 and will rearwardly displacethe latter and the connected carriage. When the carriage is moved intooperative or testing position, the driving wheels may be stopped and thecarriage then locked.

While the carriage may be displaced in the manner described; it ispreferable to drive it from a source of power which is independent ofthe vehicle motor. In this way the brakes may be tested while the enginemotor is being repaired. To accomplish this the carriage is associatedwith a driving mechanism which is actuated by the same motor which isused for testing the brakes on the wheels. In this manner a singlesource of power is utilized to effect the preliminary adjustment as wellas the actual brake test.

In the present embodiment a single source of power is employed toactuate all four brake testing units. As shown in the drawings, theelectric motor 54 is located in a suitable space provided in one end ofthe pit over which the brake testing mechanism-is located. The shaft ofthe motor 54 is connected to a speed reducing device 55, the drivenshaft 56 of which extends across the pit. The shaft 56 is preferablylocated so as not to interfere with the action of a man in the pit.Shaft 56 carries a pair of sprockets 57, each of which is associatedwith a chain 59 so as to drive the same. The chain 59 passes over asprocket 60 carried by the stationary testing unit 8 and over a fixedsprocket 28 positioned at the other accommodate a car of than thedistance between unit 4, but I wish it to dicating instrument 49.

end of the pit. Movable carriage 4 is provided with a sprocket 61adapted to cooperate with chain 59. A plurality of rollers 62 arepositioned on the carriage 4 in, such a manner as to retain chain 59 inengagement with the teeth of sprocket 61.

As is clearly shown in the drawings, sprocket 6 1 is fixed to a shaft 63carried by carriage 4. A clutching element 64 is slidably connected toshaft 63' and is provided with a groove with which is associatedactuating device 65 which in turn is operated by a lever 66. Rotatablymounted on shaft 63 is a sprocket 6'? over which passes a chain 68, bymeans of which sprocket 67 is connected with a sprocket 69 fixed toshaft I0, to which are fixed rollers 5 for moving the carriage 4 on thetrack 6. The clutching element 64 and sprocket 67 are equipped with dogsadapted to cooperate with each other to effect engagement to causesprocket 6'7 to rotate with shaft 63.

Thus, when it is desired to move carriage 4 to adjust it to a particularvehicle, lever 66 is operated to effect engagement between the clutchingelement 64 and sprocket 67. When the chain 59 is moved, rotary motionwill be imparted to shaft 63 which in turn through sprocket 6'7, chain68 and sprocket 69 will cause wheels 5 to rotate, thereby moving thecarriage 4 to a desired position. Carriage 4 also carries a shaft 71, towhich is attached a clutching collar 58 adapted to be engaged by theclutching element 64. Shaft 71 also carries a sprocket 42, over whichpasses a chain 44, which engages with a sprocket 43, fixed to a shaft 39carrying a wheel rotating roller 40. Carriage 4 also carries wheelpositioning and guiding rollers 41 and 45 respectively.

It will be appreciated that when a retarding force is applied to thewheel rotating roller, the tension in the driving chain 44 will becorrespondingly increased; consequently the tension in the flexibledriving element, which is a function of the retarding force, can bemeasured by various means, one form of which is shown in theaccompanying drawings. The structure for measuring the tension in theflexible driving element. will be described in connection with themovable testing be clearly understood that the same type of structure isassociated with each of the four testing units.

As shown in the drawings, an arm 46 is pivotally mounted on shaft '71.bifurcated and supports a shaft on which is mounted an idling roller orsprocket 4'7, adapted to engage the portion of chain 44 which is undertension when transmitting power from shaft 71 to roller 40. The upperportion of the bifurcated end of the arm 46 is equipped with anadjustable bearing member 48. As the tension in chain 44 increases,there will be a tendency for the portion of the chain under tension tostraighten out. This tendency will effect an upward movement of thebifurcated end of the arm 46.

The force tending to straighten the portion of chain 44 under tension ismeasured by a load in- An actuating rod 50 is associated with theinstrument 49 and is pivotally connected with a balance beam 51. Thefree end of the beam 51 is provided with a knife edge 52, which engagesthe bearing member 48. Knife edge 53, carried by the carriage, serves asa fulcrum for the beam 51. From the foregoing description it will beappreciated that any tendency of the portion of chain 44 under tensionto straighten will be transmitted through the beam structure to theindicating instrument 49.

Since the force exerted on the knife edge car- The free end of this armis ried by lever 51 is a function of the tension in the chain 44, whichin turn is a function of the retarding force applied to roller 40 byapplying the brake to a vehicle wheel supported thereon, the loadindicated on the dial of instrument 49 may be used to compute the torqueand brake resistance of the brake carried by the 'vehicle wheel in termsof other physical quantities. In the preferred embodiment of thisinvention the indicatinginstrument is modified somewhat; that is, thedial is calibrated so that the pointer directly indicates brakeresistance in terms of retarding torque.

These calibrations may be made, as will be understood, by measuring thetorque, of the test ving unit when operated against varying torquesimposed and indicated by a suitable prony brake or other dynamometer.Since the reading on the dial of the instrument is proportionate to theincreased resistance exerted by the brake.

application, the calibration may be easily made. The actual calibration.of a given unit will, of course, depend upon the ratio of the portionsof the-balance beam, the angularity of the several portions of the chainunder tension, and other conditions.

The testing unit 8 is mounted on a frame structure 31 which is providedwith a bumper 32 to prevent a vehicle from overrunning the testingstructure. Whe el engaging roller 33, corrugated to increase thefrictional engagement witha vehicle tire, is rotatably mounted on theframe 31.

Shaft 26 and the shaft to which roller 33 is fixed,

carry sprockets over which a driving chain 36 passes. An idling wheelpositioning roller 3'! is -spaced from roller 33 to properly positionthe vehicle wheel thereon. The frame 31 also carries a verticallypositioned guide roller 38 to pre- 1 vent the vehicle wheel fromslipping off the wheel rotating roller.

The mode of operation of the tester will have been appreciated from theforegoing description.

A vehicle, the brakes of which are to be tested,

run on to the trackways '1, until the front wheels engage with the wheelrotating rollers 33 carried by the testing units 8. The chassis of thevehicle is secured to the crossbar 9 by means of a chain or otherdevice.

The lever 66 is then shifted so that the clutching elements 64 on theunits 7 are actuated in such a manner that sprockets67 will rotate withshafts 63. to which are connected sprockets 61, engaged by the chains59. Upon energizing the motor 54, shaft 56 will be rotated through thespeed reduction device 55, and chains 59 will pass over the severalsprockets and will impart rotary motion to the shafts 63, which in turnwill cause rollers to rotate thereby moving the carriages 4 to thedesired location suitable for testing a particular vehicle. justed tothe desired position, the motor 54 is shut off, and clutching elements64 are shifted into engagement with the clutching collars 58 secured toshafts 71. a

- When the chains 59 are moved, shafts 63 and '71 will be rotated andthe rotary motion will be imparted to wheel rotating rollers 40. Alsorotary motion will be imparted to the sprockets 60 carried by testingunits 3 and rotary: motion will be transmitted through the mechanism tothe wheel rotating rollers 33. Upon applying the brakes to retard therotation of vehicle wheels, tension in the chains 44 and 36 will beincreased and this'tension in the chains will be indicated As thecarriages 4 are ad-' on the dials of the instruments 49 in terms ofbrakeretardation.

When used for operating the testing units, the

motor need run only in one direction; however,

when used for shifting the movable carriages, the motor employed may beof the reversible type, or suitable reversing gearing can be interposedbetween the motor and the carriage shifting mechanisms to eifectivelymove the carriages in the desired direction.

In the foregoing description reference has been made to a clutch orcoupling as shown in the drawings. As illustrated, this clutch isprovided with portions adapted to engage members to be rotatedtherewith; however, it is within the conof the friction type, which maybe actuated without shutting off the supply of power.

As shown in the drawings, power is transmitted in several instances bychains. I wish it to be clearly understood, however, that otherflexiblev -cept of the present invention toemploy clutches means may beemployed in appllying the concept of this invention to practicalstructure. For purposes of convenience the construction of only one sideof the brake tester contemplated by this invention has been described'indetail, but I wish it to be clearlyminderstood that each side of thecomplete testing structure is similar to the otheriIsimtheir drivingmechanism, ample unoccupied space is provided in'which a mechanic maywork and adjust the brakes being tested. The structure contemplated bythis'invention is also advanta geous in that the movable carriages maybe adjusted to the desired position with a minimum amount of exertion onthe part of the operator.

While I have shown and described the preferred embodiment of myinvention, I wish it to be understood that I do not confine myself tothe precise details of construction herein set forth by way ofillustrationes it is apparent that many changes and variations may bemade therein by those skilled in the art without departing from thespirit of the invention or exceeding the scope of the appended claims.

I claim:

1. A device for testing the brakes of a vehiclecomprising a pit havingsides and ends, brake testing units arranged on opposite sides of thepit, means arranged within the pit and at one end thereof forsimultaneously driving said units to rotate the wheels of the vehicleagainst the esistenceof their respective brakes, means to dividuallymeasure the resistance of each brake, and means for coupling said firstmentioned means with said units, arranged along the inside walls of saidpit.

2. A device for testing the, brakes of a vehicle comprising a pit havingsides and ends, brake testing units arranged on opposite sides of thepit, means arranged within-the pit and at one end thereof for drivingsaid units to rotate the wheels of the vehicle against the resistance oftheir refor coupling said first mentioned means with said units,arranged along the inside walls of said pit.

3. A device for testing the brakes of a vehicle comprising a pit havingsides. and ends, brake testing units arranged on opposite sides of thepit, a pair of said units being movable to accommodate vehicles ofdifferent wheelbase, means arranged within the pit and at one endthereof for driving said units to rotate the wheels of the vehicleagainst the resistance of their respective brakes, means to individuallymeasure the resistance of each brake, and flexible means for couplingsaid first mentioned means with said units, arranged along the insidewalls of said pit.

4. A device for testing the brakes of a vehicle comprising a pit havingsides and ends, testing units arranged on opposite sides of the pit, twoof which units are arranged to be moved longitudinally of the pit toaccommodate vehicles of different wheelbase, a motor adjacent one end ofthe pit, a shaft coupled to the motor and extending transversely acrossthe pit, and two endless flexible bands, each coupling one end of saidshaft to two of said units means to longitudinally displace the movableunits by the said motor.

5. In an apparatus for testing the brakes of a vehicle, the combinationof a front frame, a rear frame, spaced pairs of rotors mounted forrotation in said frames, respectively, a shaft rotatably mounted in saidrear frame, rollers for movably supporting said rear frame, means forrotating said shaft, and driving connections between said shaft and atleast one of said rollers.-

RAYMOND J. NORTON.

